Unlike a traditional race, winning at a photo marathon does not necessarily depend on speed.
Shutter speed is used frequently in stills photography to capture split seconds of action or increase light exposure. However, never use shutter speed to control aperture when working with video. When video shoots are concerned, shutter speed needs to be at a constant value based on camera speed – frames per second – to avoid inconsistencies.
Let’s take a look back. In the past, cameras had a mechanical rotating shutter that allowed light to expose on film and cover aperture while the film advanced to the next frame. The shutter was a rotating disc with half the disc cut out to show a shutter angle of 180 degrees.
Half the time, a shutter opens to allow light in, while the other half of the time a shutter closes to allow the film to advance one frame. When shutter speed is represented by 1/24 or 24fps, it means to say it takes 1/48sec for the shutter to open – one half rotation of the total time.
In the blink of an eye
Modern digital video cameras and DSLRs all include a shutter speed setting though rotating mechanical shutters are a thing of the past. Shutter speed principles remain the same with today’s digital sensors – it denotes the amount of time light shines onto the sensor.
At 1/50sec for PAL at 25fps, video looks normal. As shutter speed increases or decreases, more or less action can occur between frames in the video. Shutter speed in film is responsible for how smooth or jerky the video looks. With a slow shutter speed such as 1/12sec of 1/5sec, images will blend across frames and give off a dreamy quality.
On the other end of the spectrum, high shutter speeds such as 1/250sec or more give off strobe-like effects as each frame is only exposed for a short amount of time. More movement happens between frames – ideal for freeze-framing action sports, or providing stylized, dramatic effects to fight scenes.
When setting shutter speeds, keep in mind that a change of aperture might also be necessary to compensate for the amount of light streaming onto the sensor. Video cameras are able to auto-link shutter speed to exposure, while on DSLRS, it’s best to be on manual mode to maintain control of the shutter speed.